[libc-commits] [libc] [libc] Rework the RPC interface to accept runtime wave sizes (PR #80914)

[Matt Arsenault via libc-commits]

arsenm wrote:

> > The intrinsic won't actually fold out in any useful place today (only happens extremely late in the backend). You're better of linking in a wavesize constant variable
> 
> I did some basic tests at various optimization levels and didn't find a case where this changed resource usage via `-Rpass-analysis=kernel-resource-usage`. Looking at https://godbolt.org/z/T468dT1PY it at least seems capable of optimizing through very shallow branches, and this is pretty much just a single constant read and multiplication.

It is not folded out at the IR level, where all the useful optimizations happen. This is leaving dead code until we have very little attempt to do anything about it 

https://github.com/llvm/llvm-project/pull/80914